Size matters: variations in seagrass seed size at local scales affects seed performance

Abstract

Seed size can have an impact on angiosperm reproductive fitness. Ecological theory predicts plants that will produce larger seeds in stressful environments to increase the chances of seedling survival and numerous small seeds in favourable conditions to increase the number of recruits. We measured seed morphology of the seagrass Heterozostera nigricaulis from four populations under differing environmental conditions in South East Australia. Seed size and mass among sites showed consistent differences over four flowering seasons. Seeds from exposed, ephemeral meadows (Blairgowrie, Edwards Point) were 19%–53% heavier than those from larger, stable meadows at more sheltered sites (Swan Bay, Point Henry). Overall, heavier seeds from exposed sites performed better in germination experiments and persisted (remained viable) longer compared to small seeds from sheltered sites. Seeds from sheltered sites showed contrasting levels of seed performance. Small seeds from Swan Bay had the lowest germination but the proportion of viable seeds after 12 months were much higher (41%) than similar sized seeds from Point Henry (0%). There are clear life history benefits of large seeds that facilitate seed persistence and germination at exposed sites; however, the performance of smaller seeds varied between sites and may be a function of other site-specific advantages.

Seed germination demonstrates inter-annual variations in alkaline tolerance: a case study in perennial Leymus chinensis

“…These discrepancies could be attributed to variations in experimental conditions that influence germination behavior. Consistent with previous studies [ 47 , 48 ], our results demonstrated that seedlings derived from heavier seeds had greater biomass than those derived from lighter seeds, likely due to the presence of greater seed reserves in their cotyledons [ 49 , 50 ]. Intuitively, heavier seeds would seem to be advantageous because seed mineral reserves should increase as a function of total seed mass [ 51 , 52 ].…”

Developing seed‐ and shoot‐based restoration approaches for the seagrass, Zostera muelleri

“…However, this was only observed at one of our study locations (Jack's Beach), with overall germination rates too low at Corinella to detect any differences effectively. Nonetheless, seed quality is still likely to be important, with previous studies showing, for example, that larger seeds of Heterozostera nigricaulis had higher germination success and remained viable longer than smaller seeds of the same species (Smith et al 2022). Like seed viability, seed quality should also be further explored to improve germination success.…”

Seed Conservation of <i>Anaxagorea luzonensis</i> A. Gray (Annonaceae) Through Storage Behaviour and Morphology

“…de Jager et al (2019) reveal that in warm lowlands, large seeds generally spread more widely than small seeds when carried by flowing water. Besides that, large seeds that come from open-growth environments will be more adaptable than small seeds (Smith et al 2022). Small seeds are preferred by rodents as dispersal agent in the zoochory mechanism (Lang & Wang 2016).…”